Expandible packing apparatus



2 Sheets-Sheet l JNVENTOR. B. BAKEE flrraen/sys.

May 29, 1962 J. R. BAKER EXPANDIBLE PACKING APPARATUS Filed May 2, 1960May 29, 1962 J. R. BAKER EXPANDIBLE PACKING APPARATUS 2 Sheets-Sheet 2Filed May 2, 1960 INVENTOR. ZIOHN E. Bfi/(EE flTTOE/VEYS.

nite rates 3,636,639 Patented May 29, 1962 ice 3,336,639 EXPANDHBLEPACKING APPARATUS John R. Baker, Pasadena, Calif assignor to Baker OilTools, Inc., Los Angeles, Calif., a corporation of California Filed May2, 1960, Ser. No. 26,227 10 Claims. (Cl. 166201) The present inventionrelates to subsurface well bore apparatus, and more particularly topacking devices that are expandible outwardly into sealing engagementwith a surrounding well casing, or similar conduit string, disposed in awell bore.

Packers adapted to be set in Well casing, and similar conduit strings,disposed in well bores embody normally retracted packing elements orapparatus surrounding the bodies of the packers, the packing elementbeing adapted to be expanded outwardly into sealing engagement with thewell casing. At times, leakage of fluid occurs between an expandedpacking element and the well casing, or between the expanded packingelement and the body of the packer, or both. Such leakage has occurredat relatively low fluid pressures and has either remained fairlyconstant or increased as the fluid pressure increased.

An object of the present invention is to provide an expandible packingapparatus which will not leak after having been expanded against thesurrounding well casing, either around the exterior or interior of thepacking apparatus.

Another object of the invention is to provide a packing apparatusadapted to be expanded against the well casing and in which the fluidpressure in the casing is caused to provide a leakproof seal between theexterior of the packing apparatus and the well casing, and also betweenthe interior of the packing apparatus and the body on which the packingapparatus is mounted.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of severalforms in which it may be embodied. Such forms are shown in the drawingsaccompanying and forming part of the present specification. These formswill now be described in detail, for the purpose of illustrating thegeneral principles of the invention; but it is to be understood thatsuch detailed description is not to be taken in a limiting sense, sincethe scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a longitudinal section through a well packer disposed in awell casing, with the packer parts in retracted position;

FIG. 2 is a view similar to FIG. 1, with the packer parts expandedagainst the wall of the well casing;

FIG. 3 is a cross-section taken along the line 33 on FIG. 1;

FIG. 4 is a fragmentary longitudinal section through another embodimentof the invention;

FIG. 5 is a section, on a reduced scale, taken along the line 5-5 onFIG. 4.

The packing assembly or apparatus A illustrated in the drawings isadapted to form part of a well packer to be anchored in packed-oifcondition within a well casing B, or similar conduit string. The wellpacker itself can be lowered in the well casing to the desired settingpoint by means of a suitable running-in string (not shown), and itsparts can be expanded outwardly by a suitable setting apparatus (notshown). As an example, the well packer A may be run in the Well casingon a wire line secured to a setting apparatus and appropriately relatedto the well packer, all as shown, for example, in US. Patent 2,637,-402. Since the particular motive power device for set ting the packerforms no part of the present invention, it has not been illustratedherein in the interest of clarity.

The packer includes a main body 10 carrying a set of upper segmentalslips 11 adapted to be moved into engagement with the casing by an upperfrusto-conical expander 12 which is retained initially in position byone or more shear screws 13 securing it to the body. The upper slips 11are also retained initially in retracted position by shear screws 14attaching them to the upper expander. A set of lower segmental slips 15is initially held in retracted position by being attached to a lowerexpander 16 by shear screws 17, this expander being held in an initialposition by shear screws 18, or the like, threaded into the body.

The upper and lower expanders 12, 16 are longitudinally spaced from oneanother and a packing assembly or ap paratus A is disposed therebetween.This assembly in cludes a packing sleeve 19 of a pliant, elasticmaterial, such as synthetic or natural rubber, positioned between theexpanders 12, 16 and being disposed initially in a retracted positionfree from contact with the wall of the well casing B. Relative movementof the expanders or abutments 12, 16 toward one another will shorten thepacking sleeve 19 and expand it outwardly against the wall of the wellcasing, as well as inwardly into firm sealing engagement with theperiphery of the packer body 10.

The pliant, elastic material of the packing sleeve 19 may be preventedfrom cold flowing or extruding through the clearance spaces that existbetween the upper and lower expanders 12, 16 and the wall of thesurrounding casing B by an extrusion preventing device 20 placed at eachend of the packing sleeve. As specifically shown, the end 21 of theupper mandrel or abutment 12 is tapered in an upward and outwarddirection, the confronting portion 22 of the packing sleeve also beingtapered in a downward and outward direction, defining a generallytriangularly shaped groove between the tapered surfaces 21, 22 whichextend circumferentially around the abutment 12 and the confrontingportion of the packing sleeve 19. An outer metallic ring 23 ispositioned in the groove, having an inner tapered surface 24 engageableand companion to the tapered surface 21 on the abutment. This ring isalso generally triangular in cross-section. More specifically, it is ofgenerally right triangular cross-section with its outer surface 25cylindrical and with its lower surface 26 fiat and substantially normalto the axis of the well packer.

An inner ring 27, reversely arranged to the outer ring 23, is alsodisposed in the lower portion of the groove, having a tapered innersurface 28 engageable with and companion to the tapered surface 22 onthe packing sleeve 19. This inner ring is also of generally triangularcrosssection, specifically being of generally right triangularcross-section. Its outer surface 29 is cylindrical and forms acontinuation of the outer surface 25' of the other ring 23. Its uppersurface 30 is also normal to the axis of the Well packer and abuts thelower surface 26 of the outer ring.

The inner and outer rings 23, 27 substantially fill the triangulargroove defined by the tapered surfaces 21, 22 on the upper expander orabutment 12 and the packing sleeve. These rings are each split andnormally tend to remain in a retracted position, as disclosed in FIG. 1.However, the rings 23, 27 are expandible outwardly by the packing sleeve19 when the latter is shortened, to expand it outwardly against the wellcasing B so as to bring the cylindrical surfaces 25, 29 of the ringsinto engagement with the wall of the well casing.

To assure the same extent of outward expansion of the rings 23, 27, theyare keyed to one another for circumferential slidable movement withrespect to one another,

with relative radial movement being prevented by an arcuate key and slotarrangement. This key and slot arrangement consists of a circumferentialrib 32 on one of the rings 27 projecting upwardly from its upper faceand fitting within a companion circumferential groove 33 in the lowerportion of the outer ring 23. Because of the key and keyway or slotarrangement 32, 33, the rings will expand outwardly to the same extent.However, the interconnection 32, 33 between the rings will not preventsuch expansion from occurring.

A similar flow preventing device 20 is provided between the lowerexpander or abutment 1d and the lower confronting portion of the pliant,elastic packing sleeve 19.

The packing sleeve 19, when in a retracted position, has its exterior 34generally cylindrical and having a substantial running clearance withthe wall of the well casing B. The packing sleeve has an internal groove35' in its mid portion extending circumferentially around the entiresleeve, this groove having tapered sides 36 that converge toward eachother in a lateral outward direction. Fluid communication between aregion externally of the packing sleeve 19 and the inner groove 35 isprovided by a plurality of circumferentially arranged generally radialholes or passages 37 that extend from the periphery of the packingsleeve into the groove.

It is to be noted that there is a pliant, elastic seal ring 38, such asa rubber or rubber-like O ring, disposed in the internal groove 35 ofthe packing assembly. This ring may snugly fit the periphery of thepacker body 119 and is adapted to move upwardly into engagement with theupper tapered side wall 36 of the packing sleeve groove, and alsodownwardly into engagement with the lower tapered side 36 of the groove35 for the purpose of preventing leakage of fluid between the packingsleeve 19 and the packer body 10. The inner surface of the packingsleeve on opposite sides of the groove 35 may be cylindrical and engagethe periphery of the packer body It).

Initially, the upper slips 11, packing sleeve 19 together with itsextrusion preventing devices 20, and lower slips 15 are disposed intheir retracted positions, such as illustrated in FIG. 1, the lowerslips 15 being adjacent to a lower body member 40 suitably secured ontothe body itself. Through use of the wire line setting device illustratedin United States Patent 2,637,402, the well packer is lowered in thewell casing to the desired setting point, at which the packer is set inthe well bore, as by exerting an upward force on the body 10 and adownward force on the upper slips 11. Such setting action effects adisruption of the shear screws 14 holding the upper slips 11 to theupper expander 12, such slips moving downwardly along the upper expanderand into anchoring engagement with the wall of the well casing B. Thesetting force also disrupts the shear screws 13 holding the upperexpander 12 to the body 10, enabling the body to move upwardly relativeto the upper expander and upper slips, shifting the lower expander orabutment 16 toward the upper expander or abutment 12 to shorten thepacking sleeve 19 and etfect its compression between the abutments 12,16 so that it expands outwardly into engagement with the wall of thewell casing. Upward movement of the body 10 can then also disrupt theshear screw 18, 17 holding the lower expander 16 to the body and thelower slips to the lower expander, the lower body member 40 shifting thelower slips 15' upwardly along the lower expander or abutment 16 andoutwardly into anchoring engagement with the wall of the well casing,such as disclosed in FIG. 2.

The shortening and compression of the packing sleeve 19 will also causethe packing sleeve itself, and the upper and lower abutment 12, 16 toexpand the upper and lower sets of extrusion preventing rings 2%outwardly into engagement with the wall of the well casing to bridge theclearance space between the upper and lower abutments and the wall ofthe well casing )3. Although the extrusion preventing devices 26' aredisclosed, they form no part of the present invention.

However, it is preferred to use them in connection with the pliant,elastic packing sleeve 19, inasmuch as they insure the maintenance ofthe packing sleeve material at the proper location against the wellcasing B and prevent their being squeezed or extruded through theclearance spaces between the upper and lower expanders 12, 16 and thewall of the well casing.

As shown in FIG. 2, the packing apparatus A is disposed against the wellcasing B and also against the periphery of the body 1 of the tool. Theformation of the internal groove 35 in the mid portion of the packingsleeve, and also the passage holes 37 between the exterior and interiorof the packing sleeve, in effect, causes the packing sleeve 19 tofunction as two opposed cup types of packing elements that seal againstthe wall of the well casing. Thus, fluid under pressure from below theapparatus can squeeze past the outer portion of the imperforate lowerpart 1% of the packing sleeve to its mid portion where it passesinwardly through the passageways 37 in the mid portion to the interiorof the packing sleeve, and act on the upper tapered face 36 of thepacking sleeve and tend to urge the upper portion of the sleeve in anoutward direction against the well casing, thereby precluding such fluidpressure from flowing upwardly around the exterior of the upper portion19a of the packing sleeve. At the same time, this fluid under pressuretending to flow upwardly around the packing sleeve will also engage theinner seal ring 38 within the groove 35 and force it upwardly along thebody 10 of the packer and against the upper tapered side 36 of thepacking sleeve defining the inner groove. The engagemerit of the ringwith this tapered side urges the ring 38 inwardly against the peripheryof the body 10. In addition, the pressure of the fluid acting upwardlyon the seal ring 38 causes the latter to exert a mechanical force on theupper portion 19a of the packing sleeveexerted partially in an outwarddirection, and tending to maintain the upper outer portion 19a of thepacking sleeve sealed against the inner wall of the well casing B.

If, instead of the fluid pressure differential being present below thewell packer, it is present above the packing element 19, such fluidunder pressure may then pass downwardly around the exterior of theimperforate upper portion 1% of the packing sleeve to its mid portion,flowing inwardly through the holes or passageways 37 in the mid portioninto the groove 35 and acting on the lower tapered face 36 of the grooveto urge the lower portion 19b of the packing sleeve in an outwarddirection, sealing it more firmly against the wall of the well casing B,and precluding downward flow of fluid between the exterior of the lowerportion of the packing sleeve and the wall of the well casing. At thesame time, this fluid under pressure will also act in a downwarddirection on the seal ring 38, shifting it downwardly along the body It?and against the lower side 36 of the groove, placing the seal ring inleakproof engagement with the periphery of the body and also with thelower side of the groove, thereby preventing fluid from leaking betweenthe periphery of the body 10 and the lower, inner surface of the packingsleeve. Again, the fluid pressure acting on the seal ring 38 exerts amechanical force on the lower portion 19b of the packing sleevepartially in an outward direction, to insure the maintenance of a properleakproof seal between the lower portion 19b of the packing sleeve andthe wall of the well casing B.

The upper and lower parts 19a, 19b of the packing sleeve are essentiallytwo opposed cut types of packing elements, each having a base portionbearing against its adjacent abutment 12 or 16, and a lip portion at themid portion of the packing sleeve containing the passage holes 37, thelip portions being adapted to contact the well casing B upon expansionof the packing 19.

In the absence of the lateral passages 37 through the V packing sleeve,it is found that the seal ring 33 within the internal groove 35 is stilleffective to prevent leakage between the interior of the packing sleeve19 and the periphery of the packer body 1%. With a pressure differentialacting from below the packing sleeve, any fluid pressure that might passbetween the lower portion of the sleeve and the body will act upon theseal ring 38 and wedge it between the upper wall 36 and the periphery ofthe body 10, to preclude leakage between the upper portion 19a of thepacking sleeve and the periphery of the body. Conversely, with apressure differential above the packing sleeve 19, any fluid underpressure that would leak between the upper portion of the packing sleeveand the body acts upon the seal ring 38 and moves it down wardly intoengagement with the lower tapered side 36 of the groove and theperiphery of the body, precluding leakage between the lower portion 19bof the packing sleeve and the body of the tool. The arrangement justdescribed prevents leakage in both directions between the packing sleeve19 and the exterior of the body 10, whereas the arrangement illustratedin FIGS. 1 and 2, including the passages 37, not only prevents theaforenoted leakage, but is found to be more effective in also preventingleakage in both directions around the exterior of the packing sleeve 19,regardless of the direction in which fluid under pressure is acting.

In the form of invention disclosed in FIGS. 4 and 5, the internal sealring or O ring 380, made of pliant, elastic material, such as rubber orsynthetic rubber, is mounted in an internal groove in a filler ring 5!.made of cast iron, or similar material, the filler ring 51 and seal ring38a slidably engaging the periphery of the packer body 10. The fillerring 51 is of the generally triangular shape shown, conformingessentially to the shape of an internal groove 52 formed in the midportion of the packing sleeve 19d. Thus, the filler ring 51 has an uppersurface 53 inclined in an upward and inward direction and engaging acompanion inner wall 54 of the groove 52, the filler ring also having alower side S5 inclined in a downward and inward direction and engaging acompanion lower side 56 of the groove. As disclosed, the mid portion ofthe packing 19d is imperforate, inasmuch as radial holes or passages areomitted therefrom.

As a result of the movement of the upper and lower abutments 12, 16toward each other, and the shortening of the packing sleeve 19d and itsoutward expansion into engagement with the wall of the well casing B, aswell as with the periphery of the body, the foregoing arrangement isfound to seal effectively under low pressure differentials, as well ashigh pressure diflerentials, and also under intermediate ranges ofpressure. It is believed that the metal ring 51 and the seal ring 38aare effective in sealing off pressure, both internally of the packingelement and externally thereof, since any fluid pressure that tends toleak under the packing, as from below, acts upon the metal ring 51 andtends to shift the metal ring upwardly of the expanded packing sleeve19d. Because of the tapered relationship between the upper surface 53 ofthe metal ring and the companion upper side 54 of the packing sleevegroove 52, such upward movement of the metal ring tends to expand theupper portion 19!: of the packing sleeve more firmly against theperiphery of the well casing B, thereby preventing fluid from flowingupward past the exterior of the packing sleeve. The pliant, elastic sealring 38a in the metal ring 51 seals against the body 10 of the packerand precludes fluid from leaking through the interior of the packingsleeve.

On the other hand, if fluid pressure is acting on the packing assemblyfrom above, it will tend to flow between the interior of the packingsleeve 19d and the body 10, shifting the filler ring 51 downwardly ofthe body and the packing sleeve 19d, causing the lower tapered side 55of the filler ring to engage the companion side 56 of the packing sleevegroove and urge the lower portion 19 of the packing sleeve outwardlymore firmly against the wall of the well casing B, precluding leakage offluid in a downward direction between the exterior of the packing sleeveand the casing. Similarly, the seal ring 33a within the metal ring 51 isdeformed by the fluid pressure against the periphery of the packer body10 to prevent leakage of fluid between the packer body and the lowerportion of the packing sleeve.

I claim:

1. In a well tool to be lowered in a well conduit disposed in a wellbore: mounting means; upper and lower abutments mounted on said mountingmeans and movable longitudinally with respect to each other; aninherently retracted, pliant, elastic one-piece packing mounted on saidmounting means between and engageable with said abutments; said packingincluding upper and lower base portions engaging said upper and lowerabutments, respectively, a mid portion, and an imperforate portionbetween said mid portion and each base portion adapted to be expandedinto sealing engagement with the well conduit upon relative movement ofsaid abutments toward each other to move said base portions toward eachother, said mid portion having an internal circumferential spacetherewithin confronting said mounting means; and means in said spacemovable with respect to said mounting means and packing and engageablewith said mounting means and packing, said means in said spacecomprising a pliant, elastic annular member slidably sealing againstsaid mounting means.

2. In a well tool to be lowered in a well conduit disposed in a wellbore: mounting means; upper and lower abutments mounted on said mountingmeans and movable longitudinally with respect to each other; aninherently retracted, pliant, elastic one-piece packing mounted on saidmounting means between and engageable with said abutments, said packingincluding upper and lower base portions engaging said upper and lowerabutments, respectively, a mid portion, and an imperforate portionbetween said mid portion and each base portion adapted to be expandedinto sealing engagement with the well conduit upon relative movement ofsaid abutments toward each other to move said base portions toward eachother, said mid portion having an internal circumferential spacetherewithin confronting said mounting means and defined by opposed sidewalls diverging with respect to each other in a direction toward theaxis of said mounting means; and means in said space movable withrespect to said mounting means and packing and engageable with saidmounting means and side walls, said means in said space comprising apliant, elastic annular member slidably sealing against said mountingmeans.

3. In a Well tool to be lowered in a well conduit disposed in a wellbore; mounting means; upper and lower abutments mounted on said mountingmeans and movable longitudinally with respect to each other; aninherently retracted, pliant, elastic one-piece packing mounted on saidmounting means between and engageable with said abutments; said packingincluding upper and lower base portions engaging said upper and lowerabtuments, respectively, a mid portion, and an imperforate portionbetween said mid portion and each base portion adapted to be expandedinto sealing engagement with the well conduit upon relative movement ofsaid abutments toward each other to move said base portions toward eachother, said mid portion having an internal circumferential spacetherewithin confronting said mounting means; means in said space movablewith respect to said mounting means and packing and engageable with saidmounting means and packing, said means in'said space comprising apliant, elastic annular member slidably sealing against said mountingmeans; said mid portion having fluid passage means extending from itsexterior between said imperforate portions to said space to permit fluidunder pressure to pass from the exterior of said packing into said spaceand act on said imperforate portions to force said imperforate portionsoutwardly into engagement with the well conduit and also act on saidmeans in said space to force said means in said space against saidpacking and its annular member against said mounting means.

4. In a well tool to be lowered in a well conduit disposed in a wellbore: mounting means; upper and lower abutments mounted on said mountingmeans and movable longitudinally with respect to each other; aninherently retracted, pliant, elastic one-piece packing mounted on saidmounting means between and engageable with said abutments; said packingincluding upper and lower base portions engaging said upper and lowerabutments, respectively, a mid portion, and an imperforate portionbetween said mid portion and each base portion adapted to be expandedinto sealing engagement with the well conduit upon relative movement ofsaid abutments toward each other to move said base portions toward eachother, said mid portion having an internal circumferential spacetherewithin confronting said mounting means and defined by opposed sidewalls diverging with respect to each other in a direction toward theaxis of said mounting means; means in said space movable with respect tosaid mounting means and side walls, said means in said space comprisinga pliant, elastic annular member slidably sealing against said mountingmeans; said mid portion having fluid passage means extending from itsexterior between said imperforate portions to said space to permit fluidunder pressure to pass from the exterior of said packing into said spaceand act on said imperforate portions to force said imperforate portionsoutwardly into engagement with the well conduit and also act on saidmeans in said space to force said means in said space against said sidewalls and said annular member against said mounting means.

5. In a well tool to be lowered in a well conduit disposed in a wellbore: moimting means; upper and lower abutments mounted on said mountingmeans and movable longitudinally with respect to each other; aninherently retracted, pliant, elastic one-piece packing mounted on saidmounting means between and engageable with said abutments; said packingincluding upper and lower base portions engaging said upper and lowerabutments, respectively, a mid portion, and an imperforate portionbetween said mid portion and each base portion adapted to be expandedinto sealing engagement with the well conduit upon relative movement ofsaid abutments toward each other to move saidbase portions toward eachother, said mid portion having an internal circumferential spacetherewithin confronting said mounting means; and a pliant, elasticannular member in said space movable with respect to said mounting meansand packing and engageable with said mounting means and packing.

6. In a well tool to be lowered in a well conduit disposed in a wellbore: mounting means; upper and lower abutmentss mounted on saidmounting means and movable longitudinally with respect to each other; aninherently retracted, pliant, elastic one-piece packing mounted on saidmounting means between and engageable with said abutments; said packingincluding upper and lower base portions engaging said upper and lowerabutments, respectively, a mid portion, and an imperforate portionbetween said mid portion and each base portion adapted to be expandedinto sealing engagement with the well conduit upon relative movement ofsaid abutments toward each other to move said base portions toward eachother, said mid portion having an internal circumferential spacetherewithin confronting said mounting means and defined by opposed sidewalls diverging with respect to each other in a direction toward theaxis of said mounting means; and a pliant, elastic annular member insaid space movable with respect to said mounting means and packing andengageable with said mounting means and side walls.

7. In a well tool to be lowered in a well conduit disposed in a wellbore: mounting means; upper and lower abutments mounted on said mountingmeans and movable longitudinally with respect to each other; aninherently retracted, pliant, elastic one-piece packing mounted on saidmounting means between and engageable with said abutments; said packingincluding upper and lower base portions engaging said upper and lowerabutments, respectively, a mid portion, and an imperforate portionbetween said mid portion and each base portion adapted to be expandedinto sealing engagement with the well conduit upon relative movement ofsaid abutments toward each other to move said base portions toward eachother, said mid portion having an internal circumferential spacetherewithin confronting said mounting means; a pliant, elastic annularmember in said space movable with respect to said mounting means andpacking and engageable with said mounting means and packing; said midportion having fluid passage means extending from its exterior betweensaid imperforate portions to said space to permit fluid under pressureto pass from the exterior of said packing into said space and act onsaid imperforate portions to force said imperforate portions outwardlyinto engagement with the well conduit and also act on said annularmember to force said annular member against said passage and againstsaid mounting means.

8. In a well tool to be lowered in a well conduit disposed in a wellbore: mounting means; upper and lower abutments mounted on said mountingmeans and movable longitudinally with respect to each other; aninherently retracted, pliant, elastic one-piece packing mounted on saidmounting means between and engageable with said abutments; said packingincluding upper and lower base portions engaging said upper and lowerabutments, respectively, a mid portion, and an imperforate portionbetween said mid portion and each base portion adapted to be expandedinto sealing engagement with the well conduit upon relative movement ofsaid abutments toward each other to move said base portions toward eachother, said mid portion having an internal circumferential spacetherewithin confronting said mounting means and defined by opposed sidewalls diverging with respect to each in a direction toward the axis ofsaid mounting means; a pliant, elastic annular member in said spacemovable with respect to said mounting means and packing and engageablewith said mounting means and side walls; said mid portion having fluidpassage means extending from its exterior between said imperforateportions to said space to permit fluid under pressure to pass from theexterior of said packing into said space and act on said imperforateportions to force said imperforate portions outwardly into engagementwith the well conduit and also act on said annular member to force saidannular member against said side walls and against said mounting means.

9. In a well tool to be lowered in a well conduit disposed in a wellbore: mounting means; upper and lower abutments mounted on said mountingmeans and movable longitudinally with respect to each other; aninherently retracted, pliant, elastic one-piece packing mounted on saidmounting means between and engageable with said abutments; said packingincluding upper and lower base portions engaging said upper and lowerabutments, respectively, a mid pontion, and an imperforate portionbetween said mid portion and each base portion adapted to be expandedinto sealing engagement with the well conduit upon relative movement ofsaid abutments toward each other to move said base portions toward eachother, said mid portion having an internal circumferential Spacetherewithin confronting said mounting means; a ring in said spacemovable with respect to said mounting means and engageable with saidpacking, said ring having an internal circumferential groove; and apliant, elastic annular member in said groove slida'oly sealing againstsaid mounting means.

10. In a well tool to be lowered in a well conduit disposed in a wellbore: mounting means; upper and lower abutments mounted on said mountingmeans and movable longitudinally with respect to each other; aninherently retracted, pliant, elastic one-piece packing mounted on saidmounting means between and engageable with 9 said abut-merits; saidpacking including upper and lower base portions engaging said upper andlower abutments, respectively, a mid portion, and an I'm-perforateportion between said mid portion and each base portion adapted to beexpanded into sealing engagement with the Well conduit upon relativemovement of said abntments toward each other to move said base portionstoward each other, said mid portion having an internal circumferentialspace therewithin confronting said mounting means and defined by opposedside Walls diverging With respect to each other in a direction towardthe axis of said mounting means; a ring in said space movable withrespeet to said mounting means, said ring having tapered 10 sidescompanion to and engageable with the side Walls of said packing, saidring having an internal circumferential groove; and a pliant, elasticmember in said groove slidably sealing against said mounting means.

References Cited in the file of this patent UNITED STATES PATENTS1,299,368 Mack Apr. 1, 1919 2,451,762 Millikan Oct. 19, 1948 2,637,402Baker et al. May 5, 1953 2,756,827 Farrar July 31, 1956 2,764,244 PageSept. 25, 1956 2,944,604 Baker July 12, 1960

